Die rolling



Aug. 15, 1933. w. P. WITHEROW E-r AL DIE ROLLING Aug. l5, 1933.

Y w. P. WHTHEROW Er AL DIE' ROLLING 6 Sheeuts-Sheei; 2

Filed June 5, 1929 Aug. 15 1933. w, P. wnHERow ET AL VDIE ROLLING Filed June 3, `1.929

6 Sheets-Shee 3 W. P. WITHEVROW ET AL DIE ROLLING Filed June 3, 1929 6 Sheets-Sheet 5 INVENTOR umn' n m ,M a W m Rm @Li Aug. 15, 1933. v w P. wlTHERow Er AL DIE ROLLING Filed June 3, 1929 6 Sheets-Sheet 6 Patented Aug. 15, 1933 UNITED STATES PATENT OFFICE DIE ROLLING William P. Witherow,

Pittsburgh, and Paul L.

Coyle, Coraopolis, Pa., assignors to Republic Steel Corporation, Youngstown, Ohio,

a Corporation of New Jersey Application June 3, 1929. Serial No. 367,878

20 Claims.

forger is to produce a blank or, breakdown bar.

wherein masses of metal are properly distributed so as to insure that the finishing dies will fill without any danger of forging laps, and with a minimum of forging flash. The dies used in the so-called blocking operation for producing the ordinary breakdown bar are designed very largely experimentally. The breakdown dies wear and, due to the odd shape of the breakdown bar, the amount of thiswear is Very diflicult to check. As a result, the breakdown bars as actually produced are not of exactly the desired shape, and an unsatisfactory final product results.

In Witherow Patent No. 1,572,343, there is r described and claimed a manufacturing process wherein a leader' is die-rolled in a single pass with flash along the major portion of its length, thereby producing a blank having accurate dimensions and adapted for re-working, as by forging. The process described in said Witherow patent is of special value when it is desired to die-roll certain parts to finished dimensions and contour, as for example, the central I-beam portion of a front axle. In such case, only the ends needs to be re-worked by forging, and material economies are thereby effected.

Our present invention has relation to another method of producing shaped metal articles by a combination of rolling and forging. Instead of rolling with flash in a single pass and thereafter trimming the flash, We roll in a plurality of passes and then forge the blank. Ordinarily our process contemplates forging the blank all over. We are able to roll a blank with sufficient length accuracy, both as to the total length and as to component parts, to fill the forging dies, and by our multiple step rolling operation, are able to secure the desired distribution of metal in the blank.

For the manufacture of automobile front axles, cam shafts, and the like, it is necessary to have spaced bodies of metal relatively heavy in cross-section and separated by an intermediate portion of materially smaller cross-section.

In a front axle, for example, those portions of the final blank which provide stock for forging the spring pads, may be smaller than the leader only in an amount sufficient to insure draft in rolling, while the long intermediate portion which forms the central I-beam section may represent a reduction of to 60 percent from the leader.

It is important that these heavy reductions be effected in such manner as to insure the proper cross-section and to insure proper length of the component parts of the blank. It is also highly important that the several principal sections of the blanks be connected by transition portions of such a character that there is no danger seams or laps in the metal.

We provide for first rolling a blank having alternate portions each with major and minor axes, the major axis of one of such portions extending at a material angle to the major axis of another of such portions.

In order to produce the final forging blank, we provide for taking the blanks formed as above described and re-rolling them to reduce them to uniform thickness. .The effect of the first operation is to pre-shape the leader so as to determine portions thereof which it is desired to elongate, and the effect of the second operation is to work on these pre-shaped portions so as to reduce them materially in cross-section and to elongate them.

In certain flattening operations such as in the production of box strap, carriage clips, and the like, a round is squashed down into a flat. Such an operation is exemplified by the patent to Clapp et al No. 200,603, and by the patent to Brown No. 245,606. In such operations the groove is usually in one roll only, the mating roll being plain. We prefer to employ matched rolls, there being a matrix in each roll. Furthermore, instead of the leader being substantially as wide as it is high, as is the case in ordinary flattening operations, such as shown in the patents above referred to, we employ a high narrow leader which is supplied on edge. This makes it possible to effect heavy reductions in the first pass, the reductions in the second pass being relatively smaller in amount for each portion of the article.

In the design of the rolls it is important to compensate the matrix for each portion in accordance with the cross sectional size or shape of the preceding portion, as described and claimed in Witherow Patent No. 1,600,782.

By reason of the heavy and varying iedctions encountered, the leader, instead of moving at uniform speed, hitches along, and in the portions where only slight reductions are effected, there is danger of roll slippage. We provide for ragging or roughening the rolls at the points of light reduction. Ragging has heretofore been employed in blooming mills where it was desired to materially increase the angle of bite of the rolls and thus secure a heavier reduction in each pass. In the present case, however, the ragging is employed where the lightest reductions are effected. The blank is forged all over and therefore the slight roughening thereof which results from the ragging of the rolls does not show up in theflnal product.

We preferably provide a flattening pass, there being supporting means between the passes.

whereby the die rolled blank may be conveyed to the flattening pass. It is important that the mills be spaced apart a suicient distance to insure that the blank will be free of the die rolling pass before it is entered into the flattening pass. This is important not only because of the fact that the die rolled blank must be edged, but also because of the varying speeds encountered.

In the accompanying drawings, which illustrate present preferred embodiments of the invention as applied to the manufacture of an automobile front axle and an automobile cam shaft blank;l

Figure 1 is a side elevation ofr a blank produced by the flrst operation in our process and intended for the manufacture of a front axle;

Figure 2 is a top plan view thereof;

Figure "3 is a vertical section through a roll pass showing the leader entering the rolls and showing a portion of a rolled blank corresponding to a portion of Figure 1;

Figure 4 is a side elevation of the blank of Figure 1 after it has been subjected to the second operation in our process;

Figure 5 is a top plan view thereof:

Figure 6 is a view of the blank of Figure 5 after one end thereof has been forged:

Figure 7 is a front elevation of a finished axle:

Figure 8 is a transverse sectional view taken through the bottom roll of Figure 3 but to enlarged scale, and showing the circumferential dimensions of the various matrix portions;

Figure 9 is a view to enlarged scale of one end of the blank of Figure 1 and showing the longitudinal dimensions;

Figures 10 to 13, inclusive, are sections showing the roll pass at points corresponding to the section lines X-X to )GII-)HIL inclusive, on Figures 8 and 9 Figure 14 is an end view ployed;

Figures 15 to 20, inclusive, are transverse sections taken on the lines XV-XV to XX-XX, inclusive, on Figure 1;

Figure 21 is a top plan view, largely diagrammatic, showing the mill employed;

Figure 22 is a view corresponding to Figure 3 but to reduced scale and showing the flattening DB'SS;

Figure 23 is a view corresponding to Figure 1, but showing a blank intended to be made into a cam shaft;

Figure 24 is a side elevation thereof;

Figure 25 is a side elevation of the blank of Figures 23 and 24 after the same has been flattened;

Figure 26 is a top plan view of the blank of Figure 25;

Figures 27 and 28 are views corresponding to of the leader em- Figures 1 and 2 but showing another type of axle;

Figures 29 and 30 are views corresponding to Figures 4 and 5 but showing the blank of Figures 27 and 28 after the second rolling;

Figure 31 is a.view corresponding to Figure 6 but showing another type of axle; and

Figure 32 is a view corresponding to Figure 7 but showing the completed axle of r4Figure 31.

Referring first to the manufacture of the front axle blank illustrated in the drawings, a leader of the shape shown in Figure 14 and indicated by the reference character 2 is supplied to a pass formed by upper and lower die rolls 3 and 4 driven in the direction of the arrows in Figure 3, to produce a string of blanks corresponding to Figures 1 and 2. In operation, a long string of blanks in end-to-end relationship is rolled, these strings after the re-rolling operation hereinafter described, being sheared apart and individually forged.

The product of the first rolling is shown in detail in Figures 1, 2 and 15 to 20, inclusive. It comprises end portions 5, beam portions 6, pad-forming yportions 7, and a central beamforming portion 8. As best shown in Figures 1, 16 and 18, the central beam portion 8 is divided into a relatively fiat portion 8a and a relatively thicker portion 8b. This provision is made to insure that there will be adequate stock for the central I-beam when the same is made in the forging'dies, as hereinafter described.

By reference to the several sectional views, Figures 15 to 19, inclusive, it will be seen that each section of the blank of Figures 1 and 2 has a major and a minor axis, and that the major axes of the several sections extend alternately in the vertical and the horizontal direction, as viewed in the drawings. The portions 6 and 8 are relatively short as compared with the desired length of corresponding portions in the final forging blank, and it will be noted from Figure 2 that these portions all project sidewise beyond the portions 5 and 7. In the second operation the string of blanks is placed on edge and passed between flattening rolls so that when the first blank is flattened as shown in Figure 22, the portions 6 and 8 are materially reduced in width and elongated. The effect of the first rolling operation is therefore to predetermine portions of the leader which are to be materially reduced and elongated, while the effect of the second operation is to effect such reduction and elongation. Y

It is important that the several principal sections of the blanks shown inl Figures 1 and 2 be connected by transition portions of suitable shape. These transition portions are indicated at 9 and one of them is illustrated in cross-section in Figure 20. It will 'be noted from Figure 20 that there are no re-entrant angles at the corners. In the manufacture of the rolls it may be necessary to grind away the walls of the matrix so as to obtain this condition, but reentrant angles should be avoided not only because they are likely to cause laps in the nal product, but also because there is danger of so-called wipes in rolling if the roll metal is not relieved sufficiently at the transitions to insure that all re-entrant angles are eliminated.

As soon as the string of blanks, such as shown in Figures 1 and 2, has been rolled, the string while still hot is turned on edge and supplied to a pair of smooth rolls which flatten down the portions 6 and 8 and produce a string' of blanks Cil as shown in Figures 4 and 5. The portions 5 and 7 are also subjected to some rolling, but it is relatively slight in amount, being only enough to insure draft.

The mill wherein the blanks are formed is illustrated in Figure 21. The die roll pass consists of the rolls 3 and 4 and is indicated at D.R., and the flattening pass is illustrated at F.R. A roll table 10 extends from the die rolling pass to the flattening pass and is of `greater length than the length of the die rolled string. The die rolled string is therefore free of the die rolling pass and may be readily grasped by the workmans tongs and fed on edge to the flattening pass.` From the flattening rolls the string of blanks is fed to a run-out table 1l and thence passes to the hot bed 12 where it is cooled.

The flattening rolls are indicated in diagram at 13 in Figure 22. Their spacing is slightly less than the thickness of the portions 5 and 7, so that only a relatively slight draft, just sufficient to insure gripping of the string, is secured on these portions. However, since the string is on edge, the portions 6 and 8 will be heavily reduced and thereby greatly elongated.

As above stated, it is important in the design of the rolls for the die rolling pass to compensate for the preceding section as described and claimed in Witherow Patent No. 1,600,782. In Figure 8 we have shown the bottom roll of the die rolling pass in cross-section and to enlarged scale and with the circumferential dimensions properly marked. In Figure 9 we have illustrated a portion of the blank with corresponding dimensions of the article. and have also marked on Figure 9 the section lines corresponding to section lines on Figure 8. Generally speaking, the procedure in designing the roll for forming these blanks is as follows:

Starting with the smallest section of the required blank, and figuring about 18 percent reduction in the fl ttening pass for forming such smallest section, he shape of the corresponding portion as it issues from the rst pass, is determined. In calculating this section, the amount of spreading in the nal pass will, of course, be taken into account. Having thus obtained the portion of the rst pass which corresponds tothe portion of smallest section in the nal blank, the area of the leader -is determined by figuring approximately 52 percent reduction in the rst pass. The above figures are, as stated, approximate. In the rolling il-` lustrated by the drawings herein, 18 percent reduction was effected in the flattening pass at the smallest section of Wie final blank, and 51.22 percent reduction from the leader was effected in the same portion of the blank produced by the die rolling step. These two reductions together give a total reduction from the leader of approximately percent. The average front axle has a reduction of l'I0 to '15 percent from the leader required to make the largest section and by effecting 60 percent of this reduction in the'rclling operation, an .excellent blank for forging is produced. In'cert'ain cases the above. percentages may be exceeded, but the above figures have worked out satisfactorily in practice. The leader is usually figured to have an area 10 percent greater than the largest area of the blank.

The flattened blank resulting from the passinfr of the blank of Figures 1 and 2 through the rolls 13 is illustrated in Figures 4 and 5. As

shown, the nal blank is of uniform thickness, but of varying width. Portions corresponding to those portions of the blank of Figures 1 and 2 from which they were produced have been given the same reference characters in Figures 4 and 5 with a prime amxed thereto.

After the string of flattened blanks has been sheared into individual blanks, these are heated and then forged. As shown in Figure 6, one end is forged at a time. Experience shows that lighter hammers may be employed than those used for forging from bar stock. Instead' of steam hammers, board hammers can be successfully used. As is wellknown, board hammers are less expensive to operate and material savings are therefore effected. There is also a saving in the time required for forging, since a materially smaller number of blows is required for forging one of our blanks than is the case where the same product is produced from bar stock by blocking under the hammer and then finishing. In Figure 6, one end of the axle is shown forged to finished dimensions and contour and requiring only the trimming of the forging flash F. Figure '7 shows the completed axle.

As above stated, the middle portion 8 is divided into two unequal portions which in Figures 4 and 5 are indicated at 8a' and 8b. In forging an axle one end at a time, it is necessary that the dies overlap in the center so that the middle portion of the I-beam is twice under the hammer. It is found that there is sometimes a tendency for the I-beam portion which is first formed to absorb some of the stock which it is desired to form into the I-beam section for the other half of the axle, and for this reason excess stock is provided in that end which is to be last forged.

Material economies in production may be effected by our improved method. A wide variation in cross-sectional area in different parts of the forging blank may be obtained by our process of rst shaping the leader to predetermined portions which are to be reduced and elongated and then re-working to effect such reduction and elongation. In the smallest portions of the blank it is ordinarily desirable to maintain a ratio of about 3 to 1 in the reductions in the first and second passes. will ordinarily be reduced in the first and second passes only in an amount sufficient to insure proper draft.

The tendency towards skidding between the metal and the rolls is most pronounced at those portions of the first pass Where light reductions are effected, and to overcome this we rag the rolls as indicated at 14 in Figure 8. By this ragging, the skidding of the rolls on the metal is substantially' eiminated and desired lengths can `be obtained.

In Figures 23 and 24, we have shown a blank intended to be re-rolled prior to forging into cam shafts. The process of making the blank of Figures 23 and 24 is generally similar to that described for the production of the axle blank of Figures 1 and 2. It Will be noted that the blank of Figures 23 and 24 has portions 30 which are relatively thin and wide, alternating with portions 31 which are relatively high and narrow. The blanks are rolled in strings and after ilattening they have the form of Figures 25 and 26. The portions 30 have been elongated as indicated at 30', while the portions 31 have been reduced in thickness only in an amount suffi- The largest sections cient to insure proper draft. 'Ihese portions are indicated at 31.

The blank of Figures 25 and 26 is particularly suitable for cam shaft forging. The portions 30 provide ample stock for the production of the bar or shaft portions of the cam shaft, while the portions 41 provide for the bearing and cam portions thereof. f

The blank of Figures 27 and 28 is generally similar to the blank of Figures 1 and 2 except that the proportions of the various parts are different and the center portion 8c is of uniform thickness. The blank of Figures 2'7 and 28 is edged and flattened to produce the blank of Figures 29 and 30, which blank, it will be noted, is generally similar to Figures 4 and 5 and is forged one end at a time, as shown in Figure 3l, to produce the axle of Figure 32. A comparison of Figure 7 with Figure 32 will show the flexibility of our process and its adaptability to different types of articles. ,The axle of Figure 32 differs from the axle of Figure 7 in that the portions extending from the spring pads outwardly are oval in cross-section instead of being I-beam shape, and are provided with additional bosses such as are required for steering and front wheel brake mechanisms, shock absorber connections, and the like. Theblank of Figures 29 and 30 lends itself well to the.

forging of such end portions or to the forging of an I-beam section as desired. Relatively slight changes in the design of the forging blank are required for changes in the final product, and this effects material savings in the engineering cost and simplifies the rolling operations generally.

We have illustrated and described the present preferred embodiment of the invention as applied to the rolling of front axle blanks and cam shafts. It will be understood, however, that this showing is by way of illustration only land that the invention is not so limited, but

maybe otherwise embodied or practiced within the scope of the following claims.

We claim:

1. In the method of rolling, the steps consisting in rolling a leader to spread laterally portions thereof which it is desired to reduce and elongate, and then rolling the blank to effect such reduction and elongation.

2. In the method of rolling, the steps consisting in rolling a leader to laterally extend portions thereof which it is, desired to reduce and elongate, and then rolling the extended portions.

3. In the method of rolling, the steps consisting in rolling a leader so as to flatten and spread it over a major portion of its length but leaving certain portions unflattened, and then rolling the article on edge to thin and elongate the flattened portions.

4. In the method of rolling, .the steps consisting in rolling 'a leader so asy to flatten and spread it over a major portion of its length but leaving certain portions unnattened, and then rolling the article on edge to thinand elongate the flattened portions, the reduction in the first and second passes being in the ratio of about 3 to 1 in those portions of the leader corresponding to the portion of the blank of 'minimum' crosssection.

5. In the method of rolling, the. steps consisting in preshaping a leader in substantially all of A its parts to produce a blank having portions with major and minor ax the major axis in one portion extending at a substantial angle' to the major axis of another portion, and then lrerolling the blank.

6. In the method of rolling, the steps consisting in preshaping a leader in substantially all of its parts to produce a blank having portions with major and minor axes, the major axis in one portion extending at a substantial angle to the major axis of another portion, and then flattening the blank.

7. In the method of rolling, the steps consistlng in preshaping a leader in substantially all of its parts to produce a blank having portions with major and minor axes, the major axis in one portion extending at a substantial angle to the major axis of another portion, and edging the blank and reducing it to uniform thickness.

8. In the method of rolling, the steps consisty ing in preshaping a leader to produce a blank having a body portion whose cross-section has a major and a minor axis and portions at the ends of the body portion, the cross-section of such portions having a major and a minor axis with the/ major axis of the last mentioned portions extending at an angle to the major axis of the cross-section of the body portion, and rolling'the blank to elongate the body portion.

9. In the method of rolling, the steps consisting in preshaping a leader to produce a blank having a body portion whose cross-section has a major and a minor axis and portions at the ends of the body portion, the cross-section of such portions having a major and a minor axis with the major axis of the last mentioned portions extending at an angle to the major axis of the cross-section of the body portion, edging the blank and re-rolling the body portion.

10. In the method of rolling, 'the steps consisting in preshaping a leader to produce a blank having portions with major and minor axes separated by transition portions, the major axis in one portion extending at a substantial angle to the major axis of the adjacent portion, and then re-rolling the blank so as to reduce and elongate one set of such portions.

l1. In the method of rolling, the steps consisting in rolling a leader so as to preshape portions in such manner that they will project sidewise beyond intermediate portions, and rerolling the article thus formed to reduce the first mentioned portions and elongate the same.

12. A rolling mill comprising a die rolling pass, a flattening pass spaced therefrom, and a ysupport extending between the passes, said passes .being spaced to permit edging of the articles being rolled between passes.

13. A rolling mill comprising a die rolling pass, a flattening pass spaced therefrom, and a support extending between the passes, the passes being separated a distance greater than the length of a string of blanksgroduced in the 1.35 die rolling pass.

14. A rolling mill comprising a die rolling pass and a attening pass in substantialalignment, and a supporting table extending between the passes, said passes being spaced to permit edging of the articles being rolled between passes. l

15. As a new article of manufacture, a die rolled blank of substantially uniform thlckness but of varying width, the blank having a plurality of relatively narrow portions separated by relatively wider portions, at least one of the relatively narrow portions varying in itself in width.

16. As a new article of manufacture, a die rolled blank adapted to be forged into an axle,

the blank being of substantially uniform thickness but of varying Width, the blank having a central portion of relatively narrow Width, pad forming portions at the ends thereof, and end portions spaced from the pad forming portions.

17. As an article of manufacture, a die rolled blank comprising alternate portions having major and minor axes, said portions being separated by transition portions Without re-entrant angles, the major axis of one of such portions extending at an angle to the major axis of another of such portions.

18. As an article of manufacture, a die rolled blank comprising alternate portions of substantially rectangular cross-section having major and minor axes, said portions being separated by transition portions Without re-entrant angles, the major axis of one of such portions extending at an angle to the major axis of another of ysuch portions.

19. As an article of manufacture, a die rolled blank comprising alternate portions having major and minor axes, there being a relatively long central portion with portions at the end thereof symmetrically disposed relative to the central portion, the major axes on successive portions extending at an angle to one another.

20. As an article of manufacture, a die rolled blank comprising alternate portions having major and minor axes, there being a relatively long central portion with portions at the end thereof symmetrically disposed relative to the central portion, the major axes on successive portions extending at an angle to one another, one end of said central portion being heavier than the other end thereof.

WILLIAM P. WITHEROW. PAUL L. COYLE. 

